Motivation and sorting in open source software innovation

This paper studies the role of intrinsic motivation, reputation, and reciprocity in driving open source software innovation. Unlike previous literature based on survey data, we exploit the observed pattern of contributions - the .revealed preference. of developers - to infer the underlying incentives driving the decision to contribute source code. Using detailed information on code contributions and project membership, we classify software developers into distinct types and study how contributions from each developer type vary according to the open source license type and other project characteristics. We find that developers strongly sort by license type, project size, and corporate sponsorship, and that reciprocity is important only for a small subset of projects. We also show that contributions have a substantial impact on the performance of open source projects.